engleski

Functionalized TiO2 for photocatalytic degradation of neonicotinoid insecticides

Neonicotinoid insecticides, including imidacloprid, thiacloprid, thiamethoxam, clothianidin and acetamiprid have been included in the extended "Watch" list of the European commission within the water framework directive since 2018, due to the confirmed risk and danger for the aquatic environment. Their removal from contaminated waste streams is one of the major challenges with regard to solving global environmental problems [1, 2]. The aim of this work was to develop modified TiO2 photocatalysts and innovative designs of photocatalytic reactors for the decomposition of neonicotinoid insecticides under conditions of simulated solar irradiation. In this study surface functionalization of TiO2 was performed to reduce the energy band gap (Ebg) of the TiO2 and to prepare a stable immobilized photocatalytic layer with acceptable mechanical and catalytic properties under different operating conditions. A flat-plate photoreactor equipped with two lamps was designed for degradation of imidacloprid, which was used as a representative of neonicotinoid insecticides. Physicochemical, morphological and mechanical properties of the prepared photocatalytic layers were determined and their photocatalytic activity for imidacloprid degradation was tested. A comparison of photolytic and photocatalytic degradation was performed using different radiation sources for simulation of the solar light. Photocatalytic decomposition under the visible part of the solar spectrum was carried out to reduce the investment costs of the process in the real system. It was concluded that different modification methods can be used to reduce the energy band gap (Ebg) of the TiO2, but this does not necessarily mean a better conversion of imidacloprid during its photocatalytic degradation. Nevertheless, some classical synthesis routes for surface functionalization of TiO2 followed by an additional post-functionalization showed great potential to improve TiO2 activity for photocatalytic decomposition of imidacloprid under the visible part of the solar spectrum.

Neonicotinoid insecticides ; imidacloprid ; modifies TiO2 ; visible part of the solar spectrum

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